btrfs: relocation: Check cancel request after each data page read

When relocating a data extents with large large data extents, we spend
most of our time in relocate_file_extent_cluster() at stage "moving data
extents":

 1)               |  btrfs_relocate_block_group [btrfs]() {
 1)               |    relocate_file_extent_cluster [btrfs]() {
 1) $ 6586769 us  |    }
 1) + 18.260 us   |    relocate_file_extent_cluster [btrfs]();
 1) + 15.770 us   |    relocate_file_extent_cluster [btrfs]();
 1) $ 8916340 us  |  }
 1)               |  btrfs_relocate_block_group [btrfs]() {
 1)               |    relocate_file_extent_cluster [btrfs]() {
 1) $ 11611586 us |    }
 1) + 16.930 us   |    relocate_file_extent_cluster [btrfs]();
 1) + 15.870 us   |    relocate_file_extent_cluster [btrfs]();
 1) $ 14986130 us |  }

To make data relocation cancelling quicker, add extra balance cancelling
check after each page read in relocate_file_extent_cluster().

Cleanup and error handling uses the same mechanism as if the whole
process finished

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2020-02-17 14:16:53 +08:00 committed by David Sterba
parent 726a342120
commit 7f913c7cfe

View File

@ -3445,6 +3445,10 @@ static int relocate_file_extent_cluster(struct inode *inode,
btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
balance_dirty_pages_ratelimited(inode->i_mapping);
btrfs_throttle(fs_info);
if (btrfs_should_cancel_balance(fs_info)) {
ret = -ECANCELED;
goto out;
}
}
WARN_ON(nr != cluster->nr);
out:
@ -4259,6 +4263,14 @@ restart:
backref_cache_cleanup(&rc->backref_cache);
btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
/*
* Even in the case when the relocation is cancelled, we should all go
* through prepare_to_merge() and merge_reloc_roots().
*
* For error (including cancelled balance), prepare_to_merge() will
* mark all reloc trees orphan, then queue them for cleanup in
* merge_reloc_roots()
*/
err = prepare_to_merge(rc, err);
merge_reloc_roots(rc);